Debugger: Generate line numbers for class initializers with a number on the 'init' keyword (KT-16277)

Debugger tests not absent as they use the bootstrap version of kotlinc.
Obviously, this change is not present in it yet.

compiler/testData/lineNumber/custom/initBlocks.kt

@@ -28,7 +28,19 @@ class Boo {
     }
 }
 
+class Zoo {
+    init { val a = 5 }
+
+    init { val b = 6 }
+
+    init {
+        val c = 7
+    }
+
+    init { val d = 8 }
+}
+
 fun x() = ""
 
 // IGNORE_BACKEND: JVM_IR
-// 2 2 1 5 6 9 11 12 15 16 24 19 21 22 24 27 28 31
+// 2 2 1 4 5 6 9 10 11 12 14 15 16 24 19 20 21 22 24 26 27 28 31 32 34 36 37 38 40 43